1. Field of the Invention
This invention relates generally to wireless Internet Service Providers, Public Safety Service Providers and information content delivery services/providers for wireless networks and/or Public Safety Service networks. More particularly, it relates to location services for the wireless industry.
2. Background of Related Art
A proximity based service is a conventional service that utilizes location technology to allow subscriber devices to discover other subscriber devices located within a predefined proximity range. Subscriber devices that discover one another can then engage in direct peer-to-peer (p2p) communications, with or without use of a radio network infrastructure, e.g., a base station. WiFi may also be used as a medium for proximity based services.
A conventional proximity based service comprises two components: device discovery and direct communications.
The device discovery component of a proximity based service enables subscriber devices to discover other subscriber devices that are located nearby (i.e. located within a predefined proximity zone), when subscriber devices are being serviced by a network that supports proximity based services.
Moreover, the direct communications component of a proximity based service permits any two or more proximity based services enabled devices, located within a predefined proximity of one another, to engage in direct peer-to-peer (p2p) communications.
FIGS. 8A-8B depict an illustrative example of direct peer-to-peer (p2p) communications for proximity based services.
In particular, as portrayed in FIG. 7, when two or more proximity based services enabled devices 800, 810, 820 discover one another within a predefined proximity zone 830, the devices 800, 810, 820 may set up a direct peer-to-peer (p2p) communications session 840, with or without use of a radio network infrastructure (e.g. a base station) 850.
FIG. 7 depicts a conventional network-centric device discovery method.
In particular, as portrayed in step 71 of FIG. 8A, a mobile-1, a mobile-2, a mobile-3, and a mobile-4 all subscribe to the same proximity service group.
As shown in step 73, the mobile-1, mobile-2, mobile-3, and mobile-4 subsequently move into the coverage areas of a base station A and a base station B, and all are registered by mobile identifier and cell-ID (e.g. CGI or ECGI) at a proximity server.
In step 75, mobile-1 sends a device discovery request to the proximity server to request location information for mobile devices (e.g. mobile-2, mobile-3, and mobile-4) subscribed to the same proximity service group as mobile-1.
In step 77, the proximity server receives the device discovery request and initiates a location request for mobile-2, mobile-3, and mobile-4, each of which are subscribed to the same proximity service group as mobile-1.
In step 79, in the given example, the proximity server determines that mobile-2 and mobile 4 are located within a predefined proximity of mobile-1.
In step 81, upon such discovery, the proximity server sends a proximity alert message to mobile-1 to notify mobile-1 that mobile-2 and mobile-4 are both located within a predefined proximity of mobile-1.
As depicted in step 83 of FIG. 8b, the proximity server periodically sends location requests to the location server to request positioning information for mobile-3, within an expiration time duration allotted to the device discovery request as shown in step 89.
As shown in steps 85 and 87, if during the time duration allotted to the device discovery request, mobile-3 is within a predefined proximity of mobile-1, the proximity server sends a proximity alert message to mobile-1 to indicate that mobile-3 is now located within a predefined proximity of mobile-1.
If the time duration allotted to the device discovery request expires, device discovery is terminated, as portrayed in step 91 of FIG. 8b. 
In the network-centric device discovery solution portrayed in FIGS. 8A-8B, the proximity server and the location server must periodically exchange positioning information for mobile-3 throughout the time duration allotted to the device discovery request, as it is not possible to predict when mobile-3 will move within closer geographic proximity of mobile-1. Unfortunately, it is difficult to determine an optimal time interval at which the proximity server and the location server should exchange positioning information. For instance, depending on a particular speed that mobile-3 is traveling at, if a proximity location request interval is set too high, the proximity server may miss when mobile-3 (i.e. the discoveree mobile) is located within a predefined proximity of mobile-1 (e.g. mobile-3 may move in and out of a predefined proximity of mobile-1 before a location request is exchanged between the location server and the proximity server). Alternatively, if a proximity location request interval is set too low, significant network and radio resources (and also mobile battery) are consumed for positioning.
Conventional proximity based services yield a number of potential applications, e.g., friend finding, gaming, etc. A common example of a proximity based service is geofencing (AKA area event location service or area watching).
A geofencing service/area event location service is a conventional service that generates an event based notification each time a target mobile device enters or exits a predefined geographic area. A geofencing service/area event location service thus utilizes both proximity based services and predefined location information to alert requesting subscriber devices to the whereabouts of a target mobile device. For instance, a geofencing service may send an event based notification to a requesting subscriber device whenever a target mobile device enters or exits a predefined geographic area.
Existing device discovery solutions for proximity based services include: a mobile-centric device discovery solution and a network-centric device discovery solution. In a mobile-centric device discovery solution, a proximity based services enabled device uses radio technology to identify other mobile devices located within a predefined proximity zone. For instance, a proximity based services enabled device may evaluate its proximity to another mobile device by assessing radio signal strength received from that mobile device.
A network-centric device discovery solution for proximity based services is rooted in existing location based services for mobile networks.